Hyaluronan or hyaluronic acid (HA) is a high average molecular weight linear polysaccharide which is distributed widely throughout connective, epithelial, and neural tissues. HA is found primarily in the extracellular matrix and pericellular matrix, but has also been shown to occur intracellularly. The biological functions of HA include maintenance of the elastoviscosity of liquid connective tissues such as synovial fluid in the joints and the vitreous of the eye, control of tissue hydration and water transport, supramolecular assembly of proteoglycans in the extracellular matrix, and numerous receptor-mediated roles in cell detachment, mitosis, migration and tumor development.
Some of the known uses of HA include treatment of dry eye conditions, in skin care as dermal fillers and to promote wound healing. Often, dry eye conditions, skin care/dermatological procedures and wound healing are associated with pain and discomfort that typically require a separate administration of an analgesic medication. The HA formulations currently used to treat the above conditions are not effective in treating topical pain. Accordingly, there is a need in the art for methods to treat dry eye conditions effectively, to minimize skin imperfections with injectable augmentation devices, and to promote wound healing while alleviating the pain associated with these conditions.